hi kmot,
there is no special technique to keep hands steady. just relax, take a deep breath and
practise the movement over and over with air and no pull on the paint.
try on scrap first, if you need, get the other hand to support the movement.
exercise the passes on and on until you get a feel for it.
slightly pull on the paint, pass by pass, move more paint if you get it better.
you can also use a ruler or rail to spray along with one finger (pinky) touching the rail.
also try to do dots, faded lines, connecting lines and geometric figures.
i've done that for hours to get the hang of my vega 2000.
after all it's fun fun fun.
pat